Exiv2 RoadMap

[D4N]

Recently our main contributor Robin (@clanmills) decided to retire from the project effective immediately. We don't have to fool ourselves: Robin has been the driving force behind this project for roughly a decade now and invested a truly insane amount of time and effort into it. No one of the currently active contributors has either the time or the expertise to match him. This leaves us in a tough spot: how can we keep this project alive and going?

Current state

• me and @piponazo are unfortunately currently rather busy in our offline lives and cannot invest a lot of time into exiv2. I was unable to keep up with all the bug reports & pull requests, which (as expected) resulted in a lot of frustration from the other contributors.
• no one of the current contributors has the expertise and endurance matching that of @clanmills
• without @clanmills we are badly understaffed (more than before) to even perform basic maintenance
• the exiv2 webpage is run by Robin, as is the Jenkins build server which produces the release binaries

Short term steps

I propose the following to steps in the short term (until the end of 2019):

• Move the project into (hard) maintenance mode: i.e. no new features, just bugfixes.
• Ensure that we can produce a 0.27.3 release by the end of 2019: create releases on our current CI without Jenkins. A prerequisite for that is that we can build exiv2 in a reproducible fashion (which is possible, openSUSE is already doing that with one patch).
• Move the exiv2 webpage to github or gitlab pages.
• Migrate all existing svn repositories that are still out there to git under the Exiv2 org

Long term steps

I see the following options:

• We find new contributors. Imho unfortunately rather unlikely, as the past showed. We can try to raise awareness about exiv2, but unfortunately I don't really know how to make this project appealing to new contributors.
• We find a corporate sponsor, who will sponsor at least some development time. Due to the removal of the (imho) legally questionable commercial licenses, our usage of the GPL2+ and our place in a rather non-existent commercial market (Linux Desktop application dependency), we're in a pretty rough spot for this. We might try our luck with one of the big enterprise Linux vendors (RedHat, SUSE, Canonical, etc.), provided that we are in their enterprise support package.
• We rewrite the whole thing? I know this sounds crazy (and probably is), but imho exiv2 shows its age and developers like to work on the new hot stuff™ and not maintain an old application. So we might attract a few people if we decide to rewrite in a new language using new features, etc. But, this is going to alienate our current API consumers and it will take years before we achieve feature parity (if we even ever manage to do that). So not sure how realistic this is, probably not much.
• Drastically reduce the scope of Exiv2 to match only what our API consumers require (cc @cgilles @phako)?
• ???

What can we do to improve our processes?

The past showed that our current contribution process became rather complicated, which already drove away contributors. This is bad.

How can we improve for one time contributors?

• Offer patch submission via email? (WIP via sr.ht: https://git.sr.ht/~d4n/exiv2)
• Don't require strict code review from early contributors, but instead fix contributed code ourselves to reach the desired quality standard.

How can we improve the process for long term contributors?

• Pull requests don't get reviewed and cannot be merged 😞. => We could specify a ~2 week grace period for a review, where the PR author should send a weekly review reminder. If the PR author is a "proven contributor", then they can exercise their right to merge an unreviewed PR, provided that the CI is green.
• CI is flaky and breaks, only one person can fix it (@D4N for GitLab, @piponazo for Appveyor). If the person is busy, PRs are red and cannot be merged 😞. => We could move the tests to github actions, so that everyone has access to them and can fix the issues.
• PR reviews are merciless and annoying because a lot of minor stuff gets flagged. I am the culprit in this case. If this is a stop gap for many, then I will stop reviewing PRs in detail and instead amend them to fix issues that I find need fixing (provided I have time).

How can we attract more people to contribute?

• Your idea here

Any further ideas/comments/suggestions?

[D4N]

cc @tbeu @piponazo @sridharb1 @tester0077 @kevinbackhouse @derselbst @nehaljwani @fgeek @cryptomilk

[cgilles]

Hi all,

I'm always listening Exiv2 conversation, even if i'm not very active in the project.

As digiKam use Exiv2 API to handle all metadata excepted video, considerate me as present for some task. one where i'm interested is to support new image format. actually i finalize the HEIC/HEIF support in digiKam. I know that an entry exist to support this format in Exiv2, so i will be ready to check code and test new implementation for a quick move in production.

https://i.imgur.com/JmEgGNS.png
https://i.imgur.com/MlNxPLa.png

I plan also to integrate Webp, Jpegxr, FLIF, support as native loader in digiKam in the future. So All plan to support these file format in Exiv2 are in my mind.

As i practice cmake since 8 years actively in digiKam and in my office, i can help for CMake problems in Exiv2. Just ask me if necessary.

In digiKam, i implemented a lots of unit tests to check the large Qt / Exiv2 interface, with a huge collection of images. I already discovered plenty of non re-entrancy in Exiv2 API and i consolidate digiKam code with several lock, as we use multi-threading and multi-core everywhere.
In digiKam, Exiv2 API is only located in the core Qt interface. So the code in use is limited and not dispatched everywhere. Rememeber that digiKam code is more than 1.5 M of C++ code lines.

I'm also aware about the MinGW port, as we cross compile ALL the digiKam code + all dependencies for Windows under Linux using MXE. I'm in love with cross compiling, so if something do not work here, i'm ready to report a fix quickly.

digiKam has a large users base, and we publish weekly a new test version for Linux, Windows, and MacOS. If something is broken or do not work in Exiv2, we are able to report the dysfunction quickly.

Voilà, I'm here to help you if necessary if time permit.

Best

Gilles Caulier

[fgeek]

Thank you Robin Mills for all your efforts towards better open-source software. It was a pleasure to cooperate with you 👍

[phako]

Mainly some random thoughts there, sorry

• I'll probably also could check out cmake stuff, it's part of my daily work as well.

• I can provide some web hosting if necessary

• I could probably also provide some temporary infrastructure for Jenkins (would have to discuss that beforehand, though)

• What exactly was the Jenkins doing for releases that cannot be replicated by other means of CI?

• I'd suggest to drop old unmaintained code, which you've already started on master. Do only meta-data.

• While the idea of just doing a rewrite sounds always great, especially if the codebase wasn't yours to begin with, the job of doing the rewrite or ever reaching feature parity with the old codebase might be a lost fight from the start

• A rewrite does not relief you from bugfixing the old code, unfortunately

• If there's a rewrite, it needs to be consumable by C/C++ which rules out most of the "sexy" languages anyway. The only way I can actually think of would be a gradual conversion to Rust.

• I'd also be interested in getting HEIC/HEIF support as well; I was following the PR but lost track

• Attracting contributors for old stuff is usually hard. Best guess would be to get your "downstream" abord contributing, which you are obviously trying ;)

• Have you ever communicated the current lack of staffing? I wasn't really under the impression that there is any issue there

• TBH, I found the setup of the exiv2 project a tad weird. It's missing some basic infrastructure I am used to from other projects, like a user's / developers discussion forum (whatever form). Things certainly got more obvious with the move to github, though.

• Unfortunately for you, the initial decision for GPLv2, while encouraged by the FSF or rather RMS for libraries instead of going for its Lesser cousin limits corporate adoption. I suppose that this was done to encourage the use of the commercial license for those use-cases. Even more unfortunate is that this isn't something that can easily be changed without a massive headache

[tester0077]

First of all, a very big "Thank you" to Robin and his work on behalf of Exiv2. I have always found him very responsive and helpful. And the same goes for all of the other maintainers, though it seems there are only two others. :( Having worked a good deal with other people's open source code with multiple dependencies on other similar open source libraries & trying to adapt them to my needs and environment, I understand a good many of the issues they have been facing. As for the future of Eviv2, I am not sure I can offer much help, other than a few comments. My own use of Exiv2 is simply for a couple of pet projects of mine. One, started several years ago to try to analyze and, hopefully, edit image metadata for my family tree project and a second one, which I forked form an existing and apparently abandoned or stalled project, much for a similar  reason: collecting all of my images and documents for the family tree project This latter one had already been designed with Exiv2 as a basic and necessary component, but had not been using the latest version, nor was it using many of Exiv2's features as probably intended. The fact that it was using the Exiv2 libraries, was part of my decision to use it as a starting point. There is another, somewhat remotely connected, project, also part of my family tree project, namely the pyexiv?? code used as part of the Gramps project. If exiv2 were to 'stall', for my own projects, I would have to carry on as I have for others: grab the latest code and then work with it on my own and 'beat it into shape' as best I could with my needs, background, time and environment. Only recently have I started to use git, after a relatively long stable period of using SVN, though neither of these to anywhere near their full potential for serious development. Hence, using git and particularly Github and its 'cousins' by myself, requires a lot of effort and time because of their steep learning curve  - both of which are always in short supply. As for keeping exiv2 going, I had been wondering to whom the project is or would be important enough to either sponsor the project or take on the job that Robin was doing. The current maintainers might be in a much better position to assess that than myself There definitely seems to be a move towards cloud, web or handheld device based applications, though I doubt that desktops will go away completely. There is no question that another stumbling block, at least for myself, was the fact that the basic roots of both Exiv2 itself and several of the libraries it depends on, are in the Linux tradition with a whole set of different compilers and debugging environments. Porting all of this to the Windows OS involves a tremendous amount of extra software and effort. Not to mention the somewhat erratic update and maintenance cycles and their port to Windows for the libraries Exiv2 depends on. On this issue, I must commend the Exiv2 team on their work to make the porting to Windows a whole lot more convenient with the conan and Cmake utilities. Still, even using those involves considerable effort and time on all sides. As a mostly Windows user, and without wanting to get into any flame wars, I very much appreciate that work by the team. Licensing is another issue, though one which I, as a single developer with no plans to commercialize my applications, am neither qualified not interested in commenting on. Still for some people this will be THE issue and for many it will be a show stopper. Thank you all. Arnold

[derselbst]

Hi,

I am mainly a user of exiv2 (coming from gwenview) and pretty new to the team; Robin invited me recently. I'm familiar with C++, Cmake, CI. However, I'm also part of two other organizations here at GitHub, which require most of my free time. But I'll try my best to help out where I can, just ping me.

Regarding how to attract new contributors, I would like to mention that the number of contributors is actually growing. So things don't look too bad to me. Simplifying the review process sounds good to me, @D4N has raised some good ideas. A rewrite IMO would be counterproductive for this project.

[phako]

Btw, I need to release a new version of gexiv2 soonish. The document mirror on exiv2.dyndns.org is gone, I assume?

[clanmills]

exiv2.dyndns.org is gone. The release is on https://exiv2.org and the pre-release on https://pre-release.exiv2.org

A couple of obvious points about v0.27.3 (and later v0.27 dots)

1. You can publish source releases on GitHub without updating exiv2.org
2. If you publish releases on GitHub, I'm willing to update exiv2.org and build the binaries with Jenkins on the MacMini, if (and only if) the web and release code is stored on SVN. I've retired because of frustration with review/git/github.

I wish I could make the fuzzing police disappear or get them to participate in fixing security issues. They appear to have more resources than Team Exiv2. I believe Kevin is the only "fuzzer" who both reported and fixed CVEs.

[phako]

I ased regarding exvi2.dyndns.org because I received a patch to point all the docs to there. Which I will probably revert now.

Regarding the fuzzing: Unfortunately, fuzzing is quite use- and helpful. But, looking at eg. #1019 that ticket is basically useless.

• You should take away reporter's abilites to classify tickets. Classifying tickets is the project's job
• You should make fuzzing guidelines that embraces those people (I honestly have an issue with people who think writing in l33t is giving them some kind of credibility...) but also gives them a check-list of what to provide. Filing a fuzzing ticket with no reproduction material is basically use-less, it just leaves you the chance of catching such issues by code review. All fuzzers I know give you easy access to the input material that was causing an issue

[clanmills]

Jens: I seem to recall our conversation about dyndns.org in Exiv2 v0.27-RC days (about one year ago). Since then, thanks to @nehaljwani, we moved exiv2.org to a new AWS and have the pre-release web-site.

[clanmills]

I agree with you that fuzzing is useful. However the behaviour of the fuzzing police is very unhelpful and demotivating. That bug report today is a good example. I wouldn't be surprised if it's already fixed in v0.27.2 and is actually a waste of time.

[piponazo]

Hi all,

Thanks @D4N for the effort of creating this issue and giving details about the current state of the project and proposing some short/long terms actions to try to improve the situation. I find useful to have this open discussion in a github thread instead of having it in a chat.

Please find my feedback about each of the proposed steps:

Short term steps

Move the project into (hard) maintenance mode: i.e. no new features, just bugfixes.

I guess that here you are referring here about the support we can give to the project given our busy lives. I do not see myself contributing in new features during the next months, due to my personal situation, and I agree that if I find time to contribute to the project, I will do it fixing reported bugs in 0.27-maintenance.

Nonetheless, I would be more than happy to see people contributing new features to master and I will try to also dedicate time to review those PRs and guide contributors as much as possible.

Ensure that we can produce a 0.27.3 release by the end of 2019: create releases on our current CI without Jenkins. A prerequisite for that is that we can build exiv2 in a reproducible fashion (which is possible, openSUSE is already doing that with one patch).

I think it should be possible to generate the binary artifacts for 0.27.3 from travisCI and Appveyor. I could dedicate some to this topic in the next days/weeks. I remember that long ago we discussed about some security issue in travisCI regarding the deployment of binary artifacts and that's we discarded that option. Opinions about this ?

Move the exiv2 webpage to github or gitlab pages.

I like this idea. I think it is good to centralise as much as possible all the content/discussions about Exiv2 to a single place.

Migrate all existing svn repositories that are still out there to git under the Exiv2 org

I am not sure to what are you referring to here. Would you mind to develop a bit more this?

Long term steps

Drastically reduce the scope of Exiv2 to match only what our API consumers require

I think this is matching we some of the previous actions we have taken on master: i.e, to drop stuff not related with Image Metadata. Of course, any suggestions to keep improving the API would be welcomed.

We find new contributors. Imho unfortunately rather unlikely, as the past showed. We can try to raise awareness about exiv2, but unfortunately I don't really know how to make this project appealing to new contributors.

Not sure either about how to find new contributors. Exiv2 has been for me the first open source project in which I participate regularly. Somehow, after working on it for several months I felt responsible of addressing bugs and improving some specific areas ... I guess that newcomers would be interesting in addressing more interesting topics, such as adding support for new formats.

We rewrite the whole thing?

I do not think it is realistic.

Improve processes

Pull requests don't get reviewed and cannot be merged

When I had lot of spare time to work on Exiv2 (in a period in which I was switching jobs) this is what I found more annoying about our process. For big changes, I think it is fine to establish some "grace period" for a review. But most of the times we are fixing small bugs or making small improvements here and there which should not be blocked for so long. From my point of view, anyone with admin rights in the Exiv2 group, should have freedom and the good judgement to merge something quickly when the changes are mostly cosmetic or when we are dealing with fixing something in CI (just the first examples that came to my mind). In case one of these persons abuse this power, we could analyse the behaviour and decide what to do.

CI is flaky and breaks, only one person can fix it (@D4N for GitLab, @piponazo for Appveyor). If the person is busy, PRs are red and cannot be merged disappointed. => We could move the tests to github actions, so that everyone has access to them and can fix the issues.

Would it not be possible to move the permissions of Gitlab, TravisCI and Appveyor to the Exiv2 team instead of being me and @D4N the owners of these services? I will investigate with TravisCI and Appveyor (I was the one adding those services to Exiv2).

PR reviews are merciless and annoying because a lot of minor stuff gets flagged. I am the culprit in this case. If this is a stop gap for many, then I will stop reviewing PRs in detail and instead amend them to fix issues that I find need fixing (provided I have time).

I do not think this is something bad per se. I particularly always appreciate the time people dedicate to review the code I am submitting, and if the suggestions made are good, I always try to address the challenges. I also know by experience that this is not the most common way to react to the code reviews, and some people gets are less open to change things (for whatever reason).

Something that I proposed in few companies where I have worked is to tag the comments with labels indicating the importance of the comment. Something like:

• [minor] : Something that could be improved, but that is really a minor thing. Nothing would happen if it is not changed.
• [style, naming] : Cosmetic things. [naming] is normally about improving code readability. [style] is about following the project guidelines / style. Not considered as blocking issues, but it would be nice to address.
• [bug/leak] : Problems detected in the new code. Need to be addressed before accepting.
• [important / blocker] : Not a bug or leak, but something it is extremely important from the point of view of the reviewer, and it should be addressed before the PR is accepted.

I would say that we could try to be a bit more indulgent in some cases (contributors do not have much spare time or have difficulties with Git), and approve PRs unless there are open comments tagged with [bug/leak/blocker]. Then, for the project maintainers it would take probably few minutes to address the other less important comments.